The Cambridge History of English and American Literature in 18 Volumes (190721).Volume XIV. The Victorian Age, Part Two.

VIII. The Literature of Science.

§ 14. Lord Kelvin.

(Sir) William Thomson, later raised to the peerage under the title baron Kelvin, was another graduate of Cambridge of this period. (To avoid the confusion of the use of two names we will here refer to him as Kelvin.) In 1846, the year following on his first degree, he accepted a professorial chair at Glasgow, but he always kept in touch with his mathematical friends in Cambridge. Probably, he exercised a wider influence in the world at large than any of his scientific contemporaries; but his interests were so catholic that it is not easy to give any connected account of them. He possessed an almost intuitive power of realising fundamental principles. Throughout his life, ideas seem to have come to him so rapidly as to give him insufficient time for their effective development; hence, the student will search in vaid among his papers for complete and systematic expositions of his discoveries.

He began his career under the influence of Fourier, Green and Faraday. Electricity was his favourite subject of research. The writer of this sketch has heard him illustrate the progress in this subject by the fact that, in his early life, he was accustomed to explain his conclusions in it by analogies drawn from the theory of heat; but, before he died, problems in heat were commonly illustrated by analogous questions in electricity. Kelvin wrote at length on the subject of electromagnetic fields, put forward numerous suggestions about the constitution of ether and matter, and laid the foundation for a scientific system of measurement of electrical quantities. Hydrodynamics, elasticity and thermodynamics were other subjects on which he wrote, and his papers on energy and entropy were of farreaching importance. We cannot leave Kelvins work without mentioning the appearance, in 1867, of the treatise on natural philosophy by himself and his friend Peter Guthrie Tait, of Cambridge and Edinburg. In spite of Taits collaboration, this book presents an unfinished aspect; but it is suggestive, and it widely affected modes of physical thought throughout Europe.

The theory of signalling by cable originated in a correspondence between Kelvin and Stokes in 1854, and was elaborated by Kelvin and Kirchhoff, while to the former are largely due the practical applications of it. The earliest successful submarine cable laid between England and the continent dates only from 1851. Owing to the large capacity of the cable and the soakage into the insulating material, powerful currents had to be used before sensible effects could be obtained, and these difficulties increased with the length of the cable. Accordingly, when, in 1857, a cable was laid to America, the operators deemed it necessary to use electricity of a hight tension, with the result that the insulation was ruptured. Subsequently, Kelvin was given a free hand in arranging a system for use with a later cable. He evaded the old difficulties by developing extreme sensitiveness in the receiving instruments and applied the methods of Gauss and Weber for indicating the minute motions of the oscillating needle by the reflection of a ray of light from it, in effect employing a long non-material pointer. In 1870, he substituted for this method a syphon-recorder which printed the message; and this instrument is still sometimes used. He held that the transmission of signals along the wire of a submarine cable was due to an actual disturbance in the wire: whereas, according to the modern theory, propounded by Maxwell, the function of the wire is merely to guide the disturbance resident in the surrounding dielectric. Kelvin was a keen yachtsman, and was thus led to take up the problem of compasses; he also bore an active part in the development of electrical engineering. He was the owner of several patents connected with these practical applications of science.